The development of high quality multimedia devices, such as set-top boxes, high end televisions, digital televisions, personal televisions, storage products, personal digital assistants (PDAs), wireless Internet devices, etc., is leading to a variety of architectures and to more openness towards new features for these devices. The development of these new multimedia products ensures that the public will continue to increase its demand for multimedia services. Network designers and engineers are therefore continuing to design systems that are capable of meeting the increasing demand for both real time and non-real time multimedia transfer across integrated networks.
The Internet Protocol (IP)-based Internet provides a “best effort” data delivery service that does not guarantee any service level to the users. A “best effort” service over the IP network allows the complexity to stay at the end-hosts, so that the network can remain simple. The phenomenal growth of the Internet shows that this approach scales well.
On the other hand, in recent years, the IEEE 802.11 wireless local area network (WLAN) has emerged as a prevailing technology for the (indoor) broadband wireless access for mobile/portable devices. IEEE 802.11 can be considered a wireless version of “Ethernet” by virtue of supporting a “best effort” service. The IEEE 802.11 Working Group is currently defining a new supplement to the existing legacy 802.11 Medium Access Control (MAC) layer in order to support Quality of Service (QoS). The new 802.11e MAC will expand the 802.11 application domain by enabling such applications as voice and video services over wireless local area networks (WLANs).
The new IEEE 802.11e standard will constitute the industry's first true universal wireless standard supporting QoS. IEEE 802.11e will offer seamless interoperability across home, enterprise, and public access networking environments, yet still offer features that meet the unique needs of each type of network. Unlike other wireless initiatives, IEEE 802.11e is the first wireless standard that spans home and business environments by adding QoS features and multimedia support to the existing IEEE 802.11 standard, while maintaining full backward compatibility with the legacy standard.
The QoS support for multimedia traffic is critical to wireless home networks where voice, audio, and video will be delivered across multiple networked home electronic devices and personal computers. Broadband service providers view QoS and multimedia-capable home networks as an essential ingredient to offering residential customers value-added services such as video on demand, audio on demand, voice over IP and high speed Internet access.
In order to provide adequate service, some level of quantitative and qualitative determinations of the types of network services will be required. This requires adding some capability to the network to enable the network to distinguish traffic with strict timing requirements on delay, jitter and loss from other types of traffic. This is what the protocols for QoS provisioning are designed to achieve. QoS provisioning does not create bandwidth, but manages bandwidth more effectively to meet a wide range of application requirements. The goal of QoS provisioning is to provide some level of predictability and control beyond the current IP “best effort” service.
The presently existing IEEE 802.11e standard (D3.2 of July 2002) sets forth a protocol for negotiating QoS requirements for traffic streams. The D3.2 version of the IEEE 802.11e standard of July 2002 is hereby incorporated within this patent document by reference. The D3.2 version of the IEEE 802.11e standard of July 2002 will be referred to as the “D3.2 Standard.” A scheduler in a hybrid coordinator has the responsibility for determining the service schedule for each wireless station (WSTA). The scheduling is carried out so that the individual pre-negotiated QoS requirements are met. In the D3.2 Standard the service schedule is retained within the hybrid coordinator and is not made known outside of the hybrid coordinator. The actual determination of the service schedule is an algorithmic issue and is not addressed by the D3.2 Standard.
Because the service schedule that is determined by the hybrid coordinator (in the D3.2 Standard) is not known to the wireless stations, each Quality of Service (QoS) wireless station (QSTA) does not know when to expect a traffic opportunity (TXOP) to either receive downlink traffic or send uplink traffic (or send sidelink traffic). This is a problem because it is advantageous for a wireless station to conserve power by frequently entering a “power save” mode (also referred to as a “sleep” mode). The wireless station is not able to send or receive traffic when the wireless station is in the “power save” mode.
If the wireless station had prior knowledge of the service schedule within the hybrid coordinator, then the wireless station could enter into a “power save” mode when transmission opportunities (TXOPs) are not scheduled by the hybrid coordinator.
The apparatus and method disclosed and claimed in U.S. patent application Ser. No. 10/314,576 solves this problem by causing the hybrid coordinator to send a QoS service schedule to the wireless station. The wireless station then uses the QoS service schedule to perform power management by entering a “power save” mode during times when the hybrid coordinator has not scheduled any transmission opportunities.
Assume that the wireless station is in a “power save” mode at a time when the hybrid coordinator needs to send a new QoS service schedule to the wireless station. In that case the wireless station will not be able to receive the new QoS service schedule until the wireless station leaves the “power save” mode. To avoid this problem the hybrid coordinator needs to prevent the wireless station from entering a “power save” mode whenever a QoS service schedule is pending for the wireless station.
There is therefore a need in the art for an apparatus and method that will enable a hybrid coordinator in a wireless network to announce to a wireless station that a QoS service schedule is pending for the wireless station.